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Here, we elaborate a borate glass system with x La 2 O 3 – (79-x) B 2 O 3 – 20.6 Na 2 O – 0.4 CoO; (x = 0, 3, 6 and 9 mol%) glass composition utilizing the melt-quenching method, and studied through density, basic physical parameters, Fourier transforms-infrared (FTIR) and optical absorption spectroscopy. Further addition of La 2 O 3 , up to 9 mol%, affords an enhancement (25 %) in the glass density, besides other structural parameters revealing the role of lanthanum ions on the glass matrix. FTIR findings revealed the essential structural groups of borate glass like trigonal BO 3 units, tetrahedra BO 4 units, and non-bridging oxygen atoms. Here too, a propensity towards the transformation from BO 3 units to BO 4 units was obtained. The optical absorption spectra revealed the existence of Co2+ in octahedral and tetrahedral coordination and the presence of Co3+ in octahedral coordination. The blue color of the present glass was attributed to the absorption band at 571.6–580.9 nm of Co2+ cation within the tetrahedral complexes. Further analysis of the ligand field parameters revealed increased values of the splitting energy parameter of Co2+ in a tetrahedral field with higher La 2 O 3 doping indicating a higher interplay between Co cations and their surrounding ligands. Additionally, the other ligand field parameters described the environments around the cobalt ions such as bonding nature. Finally, the glass refractive index increased with the further addition of lanthanum oxide, enhancing the glass quality for the optical realm. These reported findings show excellent properties of glass host as a promising contender in optical applications. [ABSTRACT FROM AUTHOR]

Understanding the interactions in hybrid systems based on graphene and functional oxides is crucial to the applicability of graphene in real devices. Here, we present a study of the structural defects occurring on graphene during the early stages of the growth of CoO, tailored by the electronic coupling between graphene and the substrate in which it is supported: as received pristine graphene on polycrystalline copper (coupled), cleaned in ultra-high vacuum conditions to remove oxygen contamination, and graphene transferred to SiO2/Si substrates (decoupled). The CoO growth was performed at room temperature by thermal evaporation of metallic Co under a molecular oxygen atmosphere, and the early stages of the growth were investigated. On the decoupled G/SiO2/Si samples, with an initial low crystalline quality of graphene, the formation of a CoO wetting layer is observed, identifying the Stranski-Krastanov growth mode. In contrast, on coupled G/Cu samples, the Volmer-Weber growth mechanism is observed. In both sets of samples, the oxidation of graphene is low during the early stages of growth, increasing for the larger coverages. Furthermore, structural defects are developed in the graphene lattice on both substrates during the growth of CoO, which is significantly higher on decoupled G/SiO2/Si samples mainly for higher CoO coverages. When approaching the full coverage on both substrates, the CoO islands coalesce to form a continuous CoO layer with strip-like structures with diameters ranging between 70 and 150 nm. [ABSTRACT FROM AUTHOR]

A nanocomposite thin film with a moon-like structural configuration, comprised of dichalcogenides (CoS2)-CoO/Poly-2-aminothiophenol (CoS2-CoO/P2ATP), is synthesized utilizing a Co(NO3)2 and K2S2O8-driven oxidation polymerization reaction. This nanocomposite boasts impressive morphological characteristics, coupled with a noteworthy optical feature characterized by a bandgap of 1.95 eV. Hydrogen generation tests are conducted using eco-friendly, cost-effective, and readily available Red Sea water, without the need for any additional electrolytes. These experiments are conducted under various optical conditions, and the resulting Jph values are employed as an indicator of hydrogen generation efficiency. The Jph value experiences a substantial increase, transitioning from − 0.092 to − 0.13 mA/cm2 when moving from darkness to light conditions. Furthermore, under monochromatic light, the Jph values exhibit a discernible pattern, declining from − 0.175 to − 0.122 mA cm−2 as the wavelength increases from 340 to 540 nm. The consistent stability of the photocurrent for a duration of 1200 s underscores the exceptional stability and reproducibility of this photocathode in facilitating the hydrogen generation reaction. Moreover, elevating the temperature from 30 to 50 °C leads to a notable augmentation in the generated Jph, with values rising from − 0.13 to − 0.2 mA/cm2, respectively. This variation allows for the estimation of the reaction's heat, revealing a ΔH value of − 15.2 kJ/mol, indicating a spontaneous reaction and high hydrogen generation efficiency. This groundbreaking study paves the way for industrial applications of the polymer nanocomposite, enabling efficient, cost-effective, and environmentally friendly green hydrogen generation from Red Sea water. [ABSTRACT FROM AUTHOR]

[Display omitted] The step-scheme (S-scheme) heterojunction has excellent redox capability, effectively degrading organic pollutants in wastewater. Combining S-scheme heterojunction with activated persulfate advanced oxidation process reasonably can further enhance the degradation of Emerging Contaminants. Herein, a novel zero-dimensional/one-dimensional (0D/1D) CoO-CuBi 2 O 4 (CoO-CBO) photocatalyst with S-scheme heterojunction was designed by hydrothermal and solvothermal methods. The band structure and electron and hole transfer pathway of CoO-CBO were analyzed using the ex-situ and in-situ X-ray photoelectron spectroscopy (XPS), Ultraviolet and Visible Spectrophotometer (UV–Vis) and optical radiation Kelvin probe force microscope (KPFM), and the formation of S-scheme heterojunction was demonstrated. The photocatalytic activity of ·S-scheme CoO-CBO heterojunction was carried out by degrading tetracycline (TC) with activating potassium monopersulfate triple salt under visible light. Compared with pure CuBi 2 O 4 and pure CoO, 30%CoO/CuBi 2 O 4 catalyst exhibited the highest TC degradation performance after activating persulfate, degrading 89.5% of TC within 90 min. On the one hand, the S-scheme heterojunction formed between CoO and CBO had a high redox potential. On the other hand, the activation of persulfate by Co and Cu could accelerate redox cycles and facilitate the generation of active radicals such as SO 4 −, O 2 − and OH, promoting the separation of the photogenerated e− and h+ in the composite, enhancing the peroxydisulfate (PDS) activation performance and improving the degradation effect of TC. Then, a gradual decrease in the toxicity of the intermediates in the TC degradation process was detected by ECOCER. In all, this study provided an S-scheme CoO/CuBi 2 O 4 heterojunction that can activate PDS to degrade TC efficiently, which provided a new idea for the study of novel pollutant degradation and environmental toxicology. [ABSTRACT FROM AUTHOR]

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CoCrAlYSi coating has been widely used in aero-engine for its high temperature oxidation resistance. As an additive element, Hf has been studied for improving the performance of CoCrAlYSi coating. However, there is a lack of study about the influence of Hf on the high temperature oxidation behavior of CoCrAlYSi coating. In this study, we prepared customized CoCrAlYSi coatings with various HfH2 contents by laser cladding. The microstructure evolution of CoCrAlYSi coating and formation characteristics of γ-Co solution phases were discussed. The isothermal oxidation products and oxide films of CoCrAlYSi coating at 1100 °C were analyzed. Results showed that due to the addition of HfH2, the grain of CoCrAlYSi coatings was refined, together with the micro-cracks decreased. The addition of HfH2 postponed the formation of CoO during isothermal oxidation test at 1100 °C in synthetic air. The lack of CoO further postponed the formation of CoCr2O4, which may cause the failure of CoCrAlYSi coating. Meanwihle, the growth rate of Cr2O3 oxide film was decreased due to the addition of Hf, which led to the improvement of stability of CoCrAlYSi coating. [ABSTRACT FROM AUTHOR]

Photo-assisted electrocatalysis is a frontier direction of electrocatalysis in recent years, which is based on the synergistic effects of electrical and optical energy, providing a new strategy to improve the oxygen evolution reaction (OER) performance. The development of photo-assisted electrocatalysts for OER with high activity and long-term stability is of great significance for hydrogen production through water splitting. In this work, the CoO/NiFe LDH heterojunction are prepared as a photo-assisted electrocatalysts for the first time to enhance OER performance. The strong electron coupling between CoO and NiFe LDH is beneficial to change the electronic structure of catalyst and promote OER. Meanwhile, under illumination, NiFe LDH suppresses the photogenerated charge recombination of CoO and accelerates the charge transfer to promote the accumulation of holes in the CoO valence band, which can be used to further improve its OER performance. The CoO/NiFe LDH requires only an overpotential of 230 mV to achieve 10 mA cm−2 under illumination, which is 60 mV lower than that without irradiation. For water splitting, CoO/NiFe LDH heterojunction only requires 1.57 V (without light) and 1.52 V (with light) to achieve 10 mA cm−2, which is superiors to RuO 2 and most NiFe LDH based materials. Even under the irradiation of low-power LED strip, the CoO/NiFe LDH can still exhibit excellent water splitting performance and long-term stability. This work adopts a promising photo-assisted electrocatalytic strategy to promote the efficiency of water splitting, and boosts the development of LDH-based two-dimensional materials in the field of photo-assisted electrocatalysis. The synergistic effect of CoO/NiFe LDH heterojunction suppresse the photogenerated charge recombination and accelerate the charge transfer to promote the accumulation of holes in the valence band of CoO, making CoO/NiFe LDH exhibit enhanced OER performance. [Display omitted] • CoO/NiFe LDH heterojunction synthesized for photo-assisted electrocatalytic OER. • The strong electron coupling of CoO/NiFe LDH improves OER performance. • The holes accumulated on the CoO further boosts the OER performance. • CoO/NiFe LDH can be applied to the overall water splitting under illumination. [ABSTRACT FROM AUTHOR]

[Display omitted] CoO has attracted increasing attention as an electrochemical energy storage owing to its excellent redox activity and high theoretical specific capacitance. However, its low inherent electrical conductivity results in sluggish reaction kinetics, and the poor rate capability of CoO limits its widespread applications. Herein, a multiple-defect strategy of engineering oxygen vacancies and Cu-ion dopants into the low-crystalline CoO nanowires (Ov–Cu–CoO) is successfully applied. Because of the advantage of the dual defect synergetic effect, the electronic structure and charge distribution are effectively modulated, thus enhancing the electrical conductivity and enriched redox chemistry. The obtained Ov–Cu–CoO electrode exhibits a high specific capacity of 1388.6 F⋅g−1 at a current density of 1 A⋅g−1, an ultrahigh rate performance (81.2% of the capacitance retained at 20 A⋅g−1) and excellent cycling stability (101.1% after 10,000 cycles). Moreover, an asymmetric supercapacitor device with Ov–Cu–CoO as the positive electrode having a high energy density of 44.1 W⋅h⋅kg−1 at a power density of 800 W⋅kg−1, and can still remain 27.2 W⋅h⋅kg−1 at a power density of 16 kW⋅kg−1. This study demonstrates an effective strategy to enhance electrochemical performance of CoO that can be easy applied to other transition metal oxides. [ABSTRACT FROM AUTHOR]

Understanding the interactions in hybrid systems based on graphene and functional oxides is crucial to the applicability of graphene in real devices. Here, we present a study of the structural defects occurring on graphene during the early stages of the growth of CoO, tailored by the electronic coupling between graphene and the substrate in which it is supported: as received pristine graphene on polycrystalline copper (coupled), cleaned in ultra-high vacuum conditions to remove oxygen contamination, and graphene transferred to SiO2/Si substrates (decoupled). The CoO growth was performed at room temperature by thermal evaporation of metallic Co under a molecular oxygen atmosphere, and the early stages of the growth were investigated. On the decoupled G/SiO2/Si samples, with an initial low crystalline quality of graphene, the formation of a CoO wetting layer is observed, identifying the Stranski-Krastanov growth mode. In contrast, on coupled G/Cu samples, the Volmer-Weber growth mechanism is observed. In both sets of samples, the oxidation of graphene is low during the early stages of growth, increasing for the larger coverages. Furthermore, structural defects are developed in the graphene lattice on both substrates during the growth of CoO, which is significantly higher on decoupled G/SiO2/Si samples mainly for higher CoO coverages. When approaching the full coverage on both substrates, the CoO islands coalesce to form a continuous CoO layer with strip-like structures with diameters ranging between 70 and 150 nm.

To synthesize nanocomposites (NCs) comprising two different materials, a multi-step synthetic method is generally required. In this work, we report the synthesis of a heterometallic nanostructure that can be synthesized using a simple antisolvent crystallization-based method. Cu/CoO NCs composed of Cu nanoparticles and CoO nanosheets were formed by reducing mixed salt particles containing both Cu and Co precursors. The synthesized Cu/CoO NCs exhibit higher sensitivity and increased stability compared to conventional catalysts when used for the electrochemical detection of hydrogen peroxide (H2O2). [ABSTRACT FROM AUTHOR]

The present study was focused on the preparation of cobalt oxide (CoO) and barium-doped cobalt oxide (Ba-doped CoO) by following the co-precipitation method for the degradation of Emamectin benzoate pesticide in the aqueous medium. The prepared catalysts were characterized using SEM, EDX, and XRD to confirm the formation of catalysts and to observe the variation in the composition of catalysts during the degradation study. It can be suggested from the results of SEM, EDX, XRD, and FTIR analyses that Ba atom has successfully incorporated in the crystalline structure of CoO. The degradation of Emamectin benzoate pesticide was studied under the influence of different factors like solution pH, the dose of catalyst, contact time, temperature, and initial concentration of pesticide. It was observed that solution pH affects the degradation of the pesticide, and maximum degradation (23% and 54%) was found at pH 5.0 and 6.0 using CoO and Ba-doped CoO, respectively. The degradation of pesticides was found to be increased continuously (27–35% in case of CoO while 47–58% in case Ba-doped CoO) with the time of contact. However, the degradation was found to be decreased (23–3% in case of CoO while 47–44% in case Ba-doped CoO) with an increase in temperature. Likewise, in the beginning, degradation was observed to be increased up to some extent with the dose of catalyst and initial concentration of pesticide but started to decrease with further augmentation in the dose of catalyst and initial concentration of pesticide. It may be concluded from this study that doping of Ba considerably enhanced the photocatalytic ability of CoO for Emamectin benzoate pesticide. [ABSTRACT FROM AUTHOR]

We investigate US consumers' willingness to pay for cotton apparel production and country of origin attributes. Using a choice‐based conjoint experiment and information treatments, we examine the preferences of 727 US shoppers for the attributes: cotton fiber production systems and country of manufacture of the cotton fiber. Random utility theory is the basis for the survey's responses analysis to estimate willingness to pay (WTP) values for the attributes. Choices made by consumers are modeled using a mixed logit model in WTP space estimated using simulated maximum likelihood procedures. Results show that consumers are willing to pay more for cotton apparel from the United States than apparel from other countries, and more for apparel made from fiber produced in organic systems than in conventional systems. Only some subgroups of consumers were found to be affected by exposure to an information treatment regarding potential labor exploitation in cotton farms and textile mills. [EconLit Citations: D12]. [ABSTRACT FROM AUTHOR]

Oxide-based coatings are being extensively investigated as potential solutions for high-temperature solid lubrication owing to their high thermal and chemical stability. Therefore, this study aimed to investigate the tribological behavior of the thermally sprayed CoO and NiO coatings. The dry sliding wear tests were conducted against the alumina counterface at room and high temperatures using a ball-on-flat tribometer. The results revealed that the friction and wear of CoO coatings decreased with increasing temperatures, while the NiO coatings showed opposite behaviors. Ex situ (SEM/FIB, XPS) analysis revealed that the formation of thin amorphous nanocrystalline tribofilm decreased friction and wear at high temperatures. On the other hand, NiO’s high friction and wear at high temperatures were caused by the worn-out coatings, while at room temperatures, it showed the existence of brittle, cracked, and detached tribofilm on the wear track. [ABSTRACT FROM AUTHOR]

Textile wastewater becomes the primary root of environmental pollution due to the rapid infection rates of freshwater, subsurface water, soil, and air. Due to the high absorption abilities of UV and visible light, polymer nanocomposite photocatalyst films (PNPFs) are recognized as potential candidates for textile wastewater treatment. Here, we developed novel cobalt monoxide (CoO)/polyaniline (PANI) PNPFs with high photocatalytic efficiency and stability. The photocatalytic efficiencies of PANI/CoO films were estimated utilizing the degradation of organic dyes and real-textile wastewater (RTW) under various lighting conditions. PANI/CoO PNPF completely decomposed methylene blue and RTW samples in 30 and 45 min under UV light illumination, respectively. We found that the CoO nanoparticles doubled the PANI's photocatalytic decomposition rate. However, under visible light irradiation, their photocatalytic efficiencies almost halved. Moreover, PANI/CoO PNPF exhibited excellent photocatalytic stability by maintaining the photocatalytic performance for up to five cycles with over 95% removal efficiency. This study yielded an efficient and alternative polymer nanocomposite to decompose wastewater sources contaminated with various textile dyes and may be examined for industrial-scale applications in the future. [ABSTRACT FROM AUTHOR]

Currently, there is a lack of detailed knowledge about methane (CH4) reactions on metal oxide surfaces. This reaction involves in different processes such as chemical looping combustion and catalytic carbon dioxide (CO2) reforming of CH4. In this study, in situ diffuse reflectance infrared Fourier transform spectroscopy was used to investigate CH4 reaction on three transition metal oxides (CoO, CuO, and α-Fe2O3) which are commonly used in these processes at temperatures ranging from 100 °C to 700 °C. The results show that CH4 is adsorbed on the metal oxide surfaces as methoxy and formate, and then the methoxy group reacts with the metal oxide lattice oxygen forming bicarbonate. Under the effect of the used reaction temperature, the bicarbonate decomposes to CO2 and water vapor. [ABSTRACT FROM AUTHOR]

Plagued by the dual challenges of energy scarcity and environmental pollution, photocatalytic CO2 reduction has emerged as a vital engineering for collecting solar energy to convert CO2 into renewable fuels. Herein, the ultrathin CoO atomic layers with varying concentrations of oxygen vacancies are designed to photoreduce CO2 and explore the mechanism of oxygen vacancy for CO2 photoreduction. Density functional theory calculations illustrate that the oxygen vacancy not only enhances the available photoelectrons efficiency of CoO structures by improving the absorption of solar light and promoting the surface separation of electron–hole pairs, but decreases the highest occupied molecular orbital of CO2 and the potential barrier of *CO conversion to *CHO, driving the CO2 directed photoreduction toward CH4. Finally, the rich‐oxygen vacancies CoO atomic layers significantly enhance the effective photoelectrons efficiency with 136.3 μmol g−1 h−1 compared to 44.6 μmol g−1 h−1 for 2D‐CoO atomic layers. Moreover, the CH4 selectivity also rises from 39.4% to 72.4% through the regulation of oxygen vacancies. This work promotes the development of Co‐based semiconductors for CO2 photocatalytic reduction, and elucidates the mechanism of oxygen vacancy for CO2 photoreduction, which provides valuable insights for the design and optimization of similar photocatalysts in both experimental and theoretical domains. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical porous Co-CoO@NC spheres assembled by nanorods are synthesized and a temperature gradient driven mechanism is proposed for the formation of hollow architecture. • Refined Co nanoparticles was demonstrated to promote the capacity growth in lithium-ion battery by promoting the reversible transformation of SEI films. • Co-CoO@NC delivers an up-trend capacity with a high capacity of 919.3 mAh g−1 at 200 mA g−1 over 200 cycles when used as anodic material for LIBs. Transition metal oxide (TMO)-based electrodes exhibit increased capacities, yet the mechanism behind the true cause of capacity in such materials remains unclear. Herein, hierarchical porous and hollow Co-CoO@NC spheres assembled by nanorods with refined nanoparticles and amorphous carbon have been synthesized by a two-step annealing approach. A temperature gradient-driven mechanism is revealed for the evolution of the hollow structure. Compared with the solid CoO@NC spheres, the novel hierarchical of Co-CoO@NC can fully utilize the interior active material by exposing both ends of each nanorod into electrolyte. The hollow interior provides extra space for the volume variation, leading to an up-trend capacity of 919.3 mAh g−1 at 200 mA g−1 over 200 cycles. Differential capacity curves disclose that solid electrolyte interface (SEI) films reactivation partly contributes to increasing reversible capacity. The introduction of nanosized Co particles benefits the process by participating in the transformation of SEI components. This study provides a guide for constructing anodic material with exceptional electrochemical performance. [ABSTRACT FROM AUTHOR]

Materials based on graphitic carbon nitride (gCN) have drawn a great deal of attention as (photo)electrocatalysts triggering the oxygen evolution reaction (OER) in H2O splitting processes to yield hydrogen fuel. In this work, nonmonochromatized Mg Kα radiation (1253.6 eV) was used to acquire photoelectron spectroscopy data on gCN-containing composite systems supported on fluorine-doped tin oxide. The investigated materials were prepared via a straightforward decantation route to yield carbon nitride, followed by functionalization with low amounts of nanostructured co-catalysts (CoO, CoFe2O4) through radio frequency-sputtering, and final thermal treatment under an inert atmosphere. Structural and morphological analyses highlighted the formation of composite systems, in which the single constituents, featuring an intimate contact, maintained their chemical identity. This work proposes a data record including both survey scans and high-resolution spectra of C 1s, N 1s, O 1s, Co 2p, and Fe 2p core-levels for three representative specimens comprising bare and functionalized graphitic carbon nitride (gCN, gCN-CoO, and gCN-CoFe2O4). The obtained results, discussed in relation to the different chemical environments for the various elements, will be useful as a comparison for further studies in related fields. [ABSTRACT FROM AUTHOR]

The acetone gas sensor is one type of sensor being researched for its application because it detects the presence of diabetes in sufferers. Gas sensors with high sensitivity and low operating temperature have been extensively investigated for this purpose, and this research is focused on the same purpose. Synthetization and characterization of LaFeO3 with co-doping Gd2O3 and CoO thick film ceramics for acetone gas sensor was conducted. LaFeO3 was made using the co-precipitation method with 2.5% CoO for each and 0%, 2.5%, and 5% Gd2O3 variation to the LaFeO3. The LaFeO3 thick film was prepared using the screen-printing technique and calcined at 800°C for two hours. The analysis of crystal structure characterization using X-Ray Diffraction (XRD) resulted in LaFeO3 with co-doping Gd2O3 and CoO thick film ceramics having the same cubic crystal phase with smaller lattice parameters and crystallite sizes after doping were added. The results of morphology structure characterization using Scanning Electron Microscopy (SEM) showed the grain size of the LaFeO3 with co-doping 2.5% CoO and 0%, 2.5%, and 5% Gd2O3 samples to support the analysis of electric property characterization later on. The electric property characterization showed that LaFeO3 with various Gd2O3 concentrations, as part of co-doping with 2.5% CoO, resulted in higher sensitivity compared to the lacking of Gd2O3 one. In order, the maximum sensitivity values of each Gd2O3 concentration are 2.74, 3.06, and 8.76 when exposed to 270 ppm acetone gas at 310°C. Gd2O3, as part of co-doping in LaFeO3 with CoO 2.5%, has successfully increased the sensitivity to the gas sensor yet still can not meet the expectation towards the operating temperature, which is still high compared to other references.

This study examines the impact of China's perceived country image on its firms' exports based on highly disaggregated data from 2002 to 2016. Using a composite indicator that accounts for historical wars as an instrument of country image, we find that the improvement in China's perceived image significantly increases firms' exports, and this effect on developing destinations is approximately 3.4 times that on developed destinations. Further analysis shows that exports from foreign-owned and privately owned domestic firms are more sensitive to China's perceived image. The effect of country image on exports is stronger for neighboring countries and has a greater impact on consumer goods. We identify two channels through which country image affects exports, one by enhancing consumer preferences and the other by reducing trade barriers. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (gCN) is a promising n-type semiconductor widely investigated for photo-assisted water splitting, but less studied for the (photo)electrochemical degradation of aqueous organic pollutants. In these fields, attractive perspectives for advancements are offered by a proper engineering of the material properties, e.g., by depositing gCN onto conductive and porous scaffolds, tailoring its nanoscale morphology, and functionalizing it with suitable cocatalysts. The present study reports on a simple and easily controllable synthesis of gCN flakes on Ni foam substrates by electrophoretic deposition (EPD), and on their eventual decoration with Co-based cocatalysts [CoO, CoFe2O4, cobalt phosphate (CoPi)] via radio frequency (RF)-sputtering or electrodeposition. After examining the influence of processing conditions on the material characteristics, the developed systems are comparatively investigated as (photo)anodes for water splitting and photoelectrocatalysts for the degradation of a recalcitrant water pollutant [potassium hydrogen phthalate (KHP)]. The obtained results highlight that while gCN decoration with Co-based cocatalysts boosts water splitting performances, bare gCN as such is more efficient in KHP abatement, due to the occurrence of a different reaction mechanism. The related insights, provided by a multi-technique characterization, may provide valuable guidelines for the implementation of active nanomaterials in environmental remediation and sustainable solar-to-chemical energy conversion. [ABSTRACT FROM AUTHOR]

The interactions of carbon dioxide (CO2) with metal oxides are a significant subject due to the numerous applications in which this reaction is involved. Although this reaction has been extensively studied by various infrared (IR) techniques, only a few (if any) have utilized in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). DRIFTS has an essential advantage over other traditional IR techniques in that it involves minimal sample preparation before analysis. In this work, CO2 adsorption on CoO, CuO, and α‐Fe2O3 nanoparticle surfaces was investigated by using DRIFTS. While the majority of species on CoO and CuO surfaces were observed as carbonate, on α‐Fe2O3 bicarbonate was more prevalent. [ABSTRACT FROM AUTHOR]

[Display omitted] The research on the structure of advanced electrode materials is significant in the field of supercapacitors. Herein, for the first time, we propose a novel 3D/3D composite structure by a multi-step process, in which 3D hollow NiCo LDH nanocages are immobilized on 3D sea urchin-like CoO microspheres. Results show that the 3D CoO acts as an efficient and stable channel for ion diffusion, while the hollow NiCo LDH provides abundant redox-active sites. The calculated results based on density function theory (DFT) show that the CoO@NiCo LDH heterostructure has an enhanced density of states (DOS) near the Fermi level and strong adsorption capacity for OH−, indicating its excellent electrical conductivity and electrochemical reaction kinetics. As a result, the CoO@NiCo LDH electrode has an areal specific capacity of 4.71C cm−2 at a current density of 3 mA cm−2 (440.19C g−1 at 0.28 A g−1) and can still maintain 88.76 % of the initial capacitance after 5000 cycles. In addition, the assembled hybrid supercapacitor has an energy density of 5.59 mWh cm−3 at 39.54 mW cm−3. [ABSTRACT FROM AUTHOR]

This study investigates photocatalytic activity performance of CoO/ZnO nanoparticles (NPs). CoO NPs was synthesized under the hydrothermal method, followed by calcination, while CoO/ZnO NPs were successfully synthesized using the precipitation method with various molar ratios of ZnO. X-ray diffraction and selected area electron diffraction showed that CoO and ZnO have a hexagonal structure; another phase appeared as a Co3O4 spinel cubic structure. The crystallite size was decreased as the ZnO concentration increased. The transmission electron microscopy image of CoO/ZnO showed almost spherical, non-uniform, and slightly dispersed under agglomerated conditions with the particle size of 17.4 ± 3.5 and 18.1 ± 4.1 nm for molar ratio of 1:2 and 1:3, respectively. Besides, the corresponding chemical elements are confirmed by energy-dispersive X-ray spectroscopy. Fourier-transform infrared spectra showed metallic functional groups, such as Ctet2+-O, Coct3+-O, and Zn–O at 586.36, 671.23, and 410–429 cm−1 also suggests the formation of NPs. A vibrating sample magnetometer showed that the CoO/ZnO NPs exhibited antiferromagnetic properties. However, redshift absorption and band gap narrowing were observed only with the ZnO addition. The removal efficiency of photodegradation methylene blue was optimal for CoO/ZnO at a concentration of 1:2, reached 67.5% degradation within 3 h for uptake every 30 min. The photodegradation was also analyzed using a Langmuir-Hinshelwood kinetic model, resulting a rate constant (Kapp) of 6.428 × 10−3 min−1 and a half-life time (t1/2) of 107.84 ± 0.01 min at the optimum concentration. The NPs could be reused up to three times without significant change of activity. Therefore, CoO/ZnO NPs is promising photocatalyst to be developed in removal of organic pollutants in various environments.

Co/CoO multilayers are fabricated by means of radio-frequency magnetron sputtering. For the formation of each multilayer period, a Co layer is initially produced followed by natural oxidation. Platinum is used not only as buffer and capping layers, but also in the form of intermediate ultrathin layers to enhance perpendicular magnetic anisotropy. Three samples are compared with respect to the magnetic anisotropies and exchange bias between 4–300 K based on superconducting quantum interference device magnetometry measurements. Two of the multilayers are identical Co/CoO/Pt ones; one of them, however, is grown on a Co/Pt "magnetic substrate" to induce perpendicular magnetic anisotropy via exchange coupling through an ultrathin Pt intermediate layer. The third multilayer is of the form Co/CoO/Co/Pt. The use of a "magnetic substrate" results in the observation of loops with large remanence when the field applies perpendicular to the film plane. The CoO/Co interfaces lead to a significant exchange bias at low temperatures after field cooling. The largest exchange bias was observed in the film with double Co/CoO/Co interfaces. Consequently, significant perpendicular anisotropy coexists with large exchange bias, especially at low temperatures. Such samples can be potentially useful for applications related to spintronics and magnetic storage. [ABSTRACT FROM AUTHOR]

Recent events concerning the Kaspersky anti-virus software in the UK and the Android operating system in the US have highlighted the significance of the domesticity of digital products for national cybersecurity, and the importance of establishing the origin of digital products has been further brought into focus by the war in Ukraine and China's military activities around Taiwan. Digital products can contain hardware components, software elements, embedded systems, and data, and determining the country of origin (COO) in these circumstances is problematic. The aim of this research, and its main contribution, is to provide an operational framework for the application of the COO concept to address this problem. Using an inductive research methodology based on semi-structured interviews and an online survey, a 19-parameter framework for assessing the COO of digital products is developed and then applied to the case example of a mobile phone import in Turkey. This article concludes that new processes and policies are urgently required to enhance the cyber and information security for digital products, aid domestic digital technology production, and support the transition to recyclable technologies. Such developments are of significance not only for western nations concerned with data and security issues, but also for developing world countries trying to develop their own domestic digital product manufacturing capabilities. This is also of relevance to the computer end-user, who would benefit from greater clarity on the origin of digital products ahead of a purchase decision. [ABSTRACT FROM AUTHOR]

In this study, we electroplated Co and Cu on nano-spiked silicon substrates that were treated with femtosecond laser irradiations. With energy-dispersive X-ray (EDX) analysis by a scanning electron microscope (SEM), it was found that both Co and Cu are primarily coated on the spike surfaces without changing the morphology of the nanospikes. We also found that nanoscale bridges were formed, connecting the Co-coated silicon spikes. The formation of these bridges was studied and optimized through a series of time-controlled electroplating and oxidizing processes. The bridges are related to the oxidation of Co in the air. When it is irradiated with visible light, this special structure has shown a capability of interactions with carbon monoxide and carbon dioxide molecules. The electroplated cobalt may be used for gas sensors. [ABSTRACT FROM AUTHOR]

We present a holistic approach for the photovoltaic (PV) module frame improvement that considers mechanical, electrical, economic, and ecological aspects for different frame designs. In a comprehensive study, the approach is applied to exemplary PV module frame designs. The analyses performed in this study show a potential improvement path of the module frame design. This leads to an overall better module performance and helps finding the balance point between technical performance, cost, and environmental impact. Based on the results, the PV module frame design affects the aspects analyzed in this work differently. For the comparison, we defined reference frame design with 16 and 20 mm front and rear frame widths. The improvement is reached by unitizing the frame width for both sides to 18 mm and increasing its cavity width to 12 mm instead of 8.5 mm. Tuning the frame parameters in this way leads to the best balance point for frame designs in this study regarding all aspects. The mechanical finite element method (FEM) simulation results show that even a small change on the frame width has a significant influence on the stress within the solar cells. Compared with the reference frame, the optimized frame design shows 2.6% less deflection, which corresponds to around 0.7 mm. Cell‐to‐module (CTM) analysis shows that a bigger frame width lightly decreases the cover coupling power gain. Results show that increasing the front frame width from 16 to 20 mm reduces the module power by about 0.12 WP. Findings of the cost of ownership (COO) analysis suggest that the optimized frame can save around 30 g aluminum which reduces the total module cost by 0.1%. Life cycle assessment (LCA) results are directly correlated to the material mass of the corresponding design. Results show that using the optimized frame can save 0.8 kg CO2‐eq/kWP due to the saving in aluminum compared with the reference frame. [ABSTRACT FROM AUTHOR]

In a foregoing paper, the author reported evidence that the multi-spin-axis magnetic structure proposed in 1964 by van Laar is realized in antiferromagnetic CoO. Within the nonadiabatic Heisenberg model, this tetragonal body-centered structure is generated by atomic-like electrons in a special magnetic band of CoO, a mechanism that may emerge only because the nonadiabatic Heisenberg model goes beyond the adiabatic approximation. The present paper compares the band structures of the transition-metal monoxides NiO, CoO, FeO, and MnO, and shows that only CoO possesses a magnetic band which may produce the tetragonal magnetic structure proposed by van Laar. The magnetic bands of the other monoxides, NiO, FeO, and MnO, are clearly related to the monoclinic base-centered magnetic structure experimentally observed in these materials. [ABSTRACT FROM AUTHOR]

Here, this study investigated the structural changes and radiation shielding efficiency of a borate glass host modified by varying cadmium oxide (CdO) concentrations. The glass composition consisted of boron oxide (B 2 O 3 ; 80:56 mol%), sodium oxide (Na 2 O; 19.6 mol%), and cobalt oxide (CoO; 0.4 mol%), with cadmium oxide (CdO; 0:24 mol%). The glass structure was analyzed utilizing mass density and FT-infrared spectroscopy (FTIR) in the 400 to 1600 cm−1 range, while radiation shielding properties were investigated utilizing the online Phy-X software in the 0.284–1.333 MeV energy window. Notably, the addition of CdO significantly impacted the glass density, increasing it by approximately 93 % as the added CdO concentration rose from 0 to 24 mol% (i.e., from 2.507 g/cm3 to 4.849 g/cm3). FTIR analysis revealed a concurrent increase in BO 4 structural units with increasing CdO/B 2 O 3 ratios. This observation was supported by the calculated N 4 BO 4 /(BO 3 +BO 4) ratio, which increased from 40.73% for the CdO-free sample to 52.00% for the highest CdO content. This increase in BO 4 units, denser than BO 3 units, explains the observed density increase. Conversely, the concentration of non-bridging oxygens decreased from 10.14% to 4.34% with increasing CdO contents, indicating a more tightly packed glass network. Radiation shielding studies demonstrated that increasing CdO concentration from 0 to 24 mol% enhanced the shielding efficiency, evidenced by a decrease in the half-value layer parameter (HVL). The radiation protection efficacy (RPE) also increased from 0.214 to 0.426 for the CdO-free sample to the sample containing 24 mol% CdO at the investigated energy level. This finding highlights the superior shielding capability of the CdO-rich sample. Furthermore, the transmission factor (TF) was investigated for a constant thickness of 0.75 cm for glasses. The CdO-rich sample exhibited a lower TF compared to the CdO-free sample, particularly at lower energies. This finding confirms that, for a given thickness and energy, raising the cadmium oxide content in the current composition leads to an observed mitigation in the transmitted radiation. • The addition of CdO increased density, by approximately 93 % from 2.507 g/cm3 to 4.849 g/cm3. • FTIR analysis revealed a concurrent increase in BO 4 structural units from 40.73% for the CdO-free sample to 52.00% for the highest CdO content. • The concentration of non-bridging oxygens decreased from 10.14% to 4.34% with increasing CdO contents, indicating a more tightly packed glass network. • The radiation protection efficacy (RPE) also increased from 0.214 to 0.426 for the CdO-free sample to the sample containing 24 mol% CdO at the investigated energy levels. • The CdO-rich sample exhibited a lower TF compared to the CdO-free sample, particularly at lower energies. [ABSTRACT FROM AUTHOR]

In recent studies, carbon nanotube (CNTs) materials and their composites have demonstrated remarkable catalytic activity in the activation of persulfate (PS), facilitating the efficient degradation of organic pollutants. In this study, a novel Co loaded carbon nanotubes (CoO@CNT) catalyst was prepared to promote PDS activation for the degradation of sulfafurazole (SIZ). Experimental results, the CNT as a carrier effectively reduces the leaching of cobalt ions and improves the electron transport capacity，whereas the introduced Co effectively activates the PDS, promoting the generation of highly reactive radicals to degrade SIZ. Under optimized conditions (a catalyst dose of 0.2 g/L, a PDS dose of 1 g/L and an initial pH = 9.0), the obtained CoO@CNT demonstrated favorable Fenton-like performance, reaching a degradation efficiency of 95.55% within 30 min. Furthermore, density functional theory (DFT) calculations demonstrate that the introduction of cobalt (Co) accelerates electron transfer, promoting the decomposition of PDS while facilitating the Co2+/Co3+ redox cycling. We further employed the environmental chemistry and risk assessment system (ECOSAR) to evaluate the ecological toxicity of intermediate products, revealing a significant reduction in ecological toxicity associated with this degradation process, thereby confirming its environmental harmlessness. Through batch experiments and studies, we gained a comprehensive understanding of the mechanism and influencing factors of CoO@CNT in the role of SIZ degradation, and provided robust support for evaluating the ecological toxicity of degradation products. This study provides a significant strategy for the development of efficient catalysts incorporating Co for the environmentally friendly degradation of organic pollutants. • The introduced CoO effectively activate the PDS, promoting the generation of highly reactive radicals to degrade SIZ. • DFT calculations demonstrate that the introduction of Co accelerates electron transfer, promoting the decomposition of PDS. • We also assessed the ecological toxicity of intermediate products using the ECOSAR. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hollow spheres structures Co/CoO/ZnO@NC electrod material is prepared. • The hollow sphere uses Co as the core and CoO/ZnO@NC particles as the shell. • It has the good rate capability (735 and 515 mAh/g at 100 mA g−1 and 2000 mA g−1 respectively). • It has excellent cycling stability (702mAh/g at 100 mAg−1 after 100 cycles). Transition metal oxides have become a potential anode material for LIBs due to their large theoretical capacity, low cost, abundant resources. However, significant volume changes and severe particle aggregation occur during charge/discharge process. In this work, it is found that the composite of dual component active TMO and single metal, and coating by doped carbon are the effective methods to improve the electrochemical performance and adapt to volume changes in storing lithium. The specific process is based on the co-precipitation of Zn and Co ions in the presence of 2-methylimidazolium salts to produce imidazolium salt frameworks (ZIFs) of bimetallic zeolites, which are then thermally decomposed to form hollow spheres structures Co/CoO/ZnO@NC. The hollow sphere uses Co as the core and CoO/ZnO@NC particles coated with nitrogen doped carbon layer as the shell. These spherical structures exhibit excellent electrochemical performance, high reversible capacity, excellent cycling stability (702 mAh/g at 100 mAg−1 after 100 cycles), and good rate capability (735 mAh/g and 515 mAh/g at 100 mA g−1 and 2000 mA g−1 respectively). [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (gCN) is a promising n-type semiconductor widely investigated for photo-assisted water splitting, but less studied for the (photo)electrochemical degradation of aqueous organic pollutants. In these fields, attractive perspectives for advancements are offered by a proper engineering of the material properties, e.g., by depositing gCN onto conductive and porous scaffolds, tailoring its nanoscale morphology, and functionalizing it with suitable cocatalysts. The present study reports on a simple and easily controllable synthesis of gCN flakes on Ni foam substrates by electrophoretic deposition (EPD), and on their eventual decoration with Co-based cocatalysts [CoO, CoFe2O4, cobalt phosphate (CoPi)] via radio frequency (RF)-sputtering or electrodeposition. After examining the influence of processing conditions on the material characteristics, the developed systems are comparatively investigated as (photo)anodes for water splitting and photoelectrocatalysts for the degradation of a recalcitrant water pollutant [potassium hydrogen phthalate (KHP)]. The obtained results highlight that while gCN decoration with Co-based cocatalysts boosts water splitting performances, bare gCN as such is more efficient in KHP abatement, due to the occurrence of a different reaction mechanism. The related insights, provided by a multi-technique characterization, may provide valuable guidelines for the implementation of active nanomaterials in environmental remediation and sustainable solar-to-chemical energy conversion.

Herein, we prepared CoO nanozymes with three types of enzyme catalytic activities for the first time, which have SOD-like, CAT-like, and POD-like catalytic activities. This is the first study to report the preparation of CoO nanoparticles with three types of enzyme catalytic activities by the one-pot method. By modifying the surface of CoO nanozymes with a carboxyl group, its biocompatibility enhanced, so it can be used in the field of life sciences. In vitro cytotoxicity and anti-H2O2-induced ROS experiments proved that CoO nanozymes can protect HaCaT cells against ROS and cytotoxicity induced by H2O2. In addition, an atopic dermatitis (AD) mouse model was established by topical application of MC903, which verified the anti-inflammatory effect of CoO nanozymes on the AD mouse model. Traditional drugs for the treatment of AD, such as dexamethasone, have significant side-effects. The side-effects include skin burns, telangiectasias, and even serious drug dependence. CoO nano-enzymes have a low cytotoxicity and its multiple enzyme-like catalytic activities can effectively protect cells and tissues in ROS environments, which proves that CoO nano-enzymes have high application potential in the field of anti-inflammation. [ABSTRACT FROM AUTHOR]

[Display omitted] • N -doped biochar with CoO loaded (CoO-N/BC) was successfully prepared via the simple synthesis process of impregnation and carbonization. • The superior catalytic efficiency of CoO-N/BC was ascribed to the directional flow of electrons on well-organized carbon network. • Both radical and non-radical process conjointly led to the stepwise decomposition of CIP. • Nitrogen doped sites and Co2+ catalysis sites as well as defects formed in sp2-hybridized carbon network were supposed to be the active sites for PMS. Burning lignocellulosic biomass wastes in an outdoor atmosphere has placed heavy burden on ecological environment and increased risk on human health. Converting solid agricultural wastes into functional materials is a research hotspot. In this study, N -doped and CoO-loaded carbocatalyst (CoO-N/BC) was successfully synthesized from the cotton stalk biomass via a simple synthesis process of impregnation and carbonization. Compared with cotton stalk biomass derived pristine biochar, the CoO-N/BC possessed a higher specific surface area (466.631 m2 g−1 vs 286.684 m2 g−1) as well as a better catalytic performance in the activation of peroxymonosulfate (PMS) for CIP degradation. The superior catalytic efficiency was ascribed to the directional flow of electrons on the well-organized carbon network of CoO-N/BC, which accelerated electron migration and improved electron conduction ability. Based on the results of radical quenching experiment and electron paramagnetic resonance (EPR), both radical and non-radical process conjointly led to the stepwise decomposition of CIP, and singlet oxygen (1O 2) mediated non-radical pathway was discovered to play a dominant role. Besides, the carbon-bridge mediated non-radical pathway was proved to accelerate this degradation process through the experiments of prolong the time of adding CIP at different time intervals. Nitrogen doped sites and CoO active sites as well as defects formed in sp2-hybridized carbon network were supposed to be the active sites for PMS. Furthermore, EIS and LSV were employed to confirm the electron transfer mediated non-radical process of reaction system. This work provides a modified strategy for the disposition of lignocellulosic biomass wastes and illuminates the underlying mechanism of heterogeneous catalysis by CoO-N/BC. [ABSTRACT FROM AUTHOR]

It is a great challenge to synthesize efficient electrocatalysts for overall water splitting, especially non‐noble metal catalysts. Herein, one‐dimensional polycrystalline nanoneedles composed of CoO−Co9S8 nano heterostructures, in situ grown on carbon fiber paper are prepared for efficient overall water electrolysis. Due to strong electronic coupling, charge densities of Co2+/Co3+ in Co9S8 and Co2+ in CoO are favorably modified at the interface of CoO and Co9S8, resulting in optimized reaction intermediates absorption and greatly enhanced bifunctional HER/OER activities. CoO−Co9S8/CFP delivers a current density of 10 mA cm−2 in alkaline electrolyte at overpotentials of 184 mV and 270 mV for HER and OER, respectively. When used as electrocatalyst for overall water splitting, it needs a low cell potential of 1.66 V to realize water electrolysis at 10 mA cm−2. This work provides a new strategy to tune the electronic structures of transitional metal active sites via constructing nano heterostructures for efficient water electrolysis. [ABSTRACT FROM AUTHOR]

In the current work, the effect of increasing the number of atoms on the geometric, electronics and spectral properties of the PVA-CoO-SiC) structure was studied by Gaussian 0.9 program with help of Gaussian View 0.5 using density function theory, (DFT) with (LanL2DZ). The geometrical, electronic and spectroscopic properties of (PVA-CoO-SiC) (46Atom) and (PVA-CoO-SiC) (91Atom). The geometric properties included improving geometric optimization (bonds and angles).As for the electronics properties such as (Ionization potential,Electron affinity, Chemical hardness,Chemical softness, Electronegativity, Total energy, cohesive energy, energy gap, Electrophilicity and density of states),in addition to spectral properties, that involved (IR, Raman,UV-Visible). There was a direct effect on all the properties of the studied structure when number of atoms of the structure increase. The obtained results indicated to the PVA-CoO-SiC can be used for various modern applications. [ABSTRACT FROM AUTHOR]

In this study, we electroplated Co and Cu on nano-spiked silicon substrates that were treated with femtosecond laser irradiations. With energy-dispersive X-ray (EDX) analysis by a scanning electron microscope (SEM), it was found that both Co and Cu are primarily coated on the spike surfaces without changing the morphology of the nanospikes. We also found that nanoscale bridges were formed, connecting the Co-coated silicon spikes. The formation of these bridges was studied and optimized through a series of time-controlled electroplating and oxidizing processes. The bridges are related to the oxidation of Co in the air. When it is irradiated with visible light, this special structure has shown a capability of interactions with carbon monoxide and carbon dioxide molecules. The electroplated cobalt may be used for gas sensors.

In this study, the impact of cobalt oxide (CoO) on the structure, stability, linear and nonlinear optical parameters of B 2 O 3 –Na 2 O–ZnO glasses was scrutinized. A series of glass system (ZnCoNaB-glasses) was successfully prepared through the melt quenching approach. Optical absorbance, reflectance, transmittance and FTIR spectroscopy were performed for all ZnCoNaB-glasses. The FTIR results showed that the BO 4 units are enhanced while nonbridging oxygens are decreased with further CoO addition. Furthermore, ZnO exists as four-coordinated [ZnO 4 ] units and these units decreased with further doping of CoO. These structural variations produce a decreasing impact in Urbach energy and nonlinear refractive index, meanwhile enhance the glass stability. Further, the metallization criterion (M) values indicate that our glass samples can be used for a new generation of nonlinear optical glasses. The preceding results can predict that the investigated ZnCoNaB-glasses will be utilized in versatile applications; especially optical switching and computing. [ABSTRACT FROM AUTHOR]

The influences of cobalt oxide (CoO) additions on the structure, optical transitions, ligand field parameters and stability of lithium phosphate glasses have been investigated. A series of glass systems (LiPhCo-glasses) was successfully prepared through the melt quenching approach. The amorphous nature was confirmed from X-ray diffraction measurements. The density and molar volume followed the typical opposite behavior, where the latter showed a decreasing behavior with CoO additions. Furthermore, it was found that the LiPhCo-glasses gradually changed their color from colorless (Co-free sample) into bluish glasses with CoO additions, thereby evidencing the presence of Co2+ ions. This is consistent with the absorption band identified in the optical absorption spectra at ~562–572 nm, which is related to 4A 2 (4F) →4T 1 (4P) electronic transitions of Co2+ (3d7 electronic configuration) in tetrahedral symmetry. Additional absorption band is detected at ~1412–1448 nm, which is correlated to 4A 2 (4F) →4T 1 (4F) transitions of Co2+ ions in tetrahedral symmetry. These two absorption bands were employed to study the ligand field splitting (10 D q t)and Racah parameter (B), which sheds the light into the bonding character between Co ions and its ligands. The analysis showed that 10 D q t (B) is increased (reduced) indicating more covalency and less stability within the glass matrix with Co additions. [ABSTRACT FROM AUTHOR]

A simple two-step method for the preparation of heterojunction with oxygen vacancy (V o -ZnO/CoO) nanowire arrays for high-performance supercapacitors. [Display omitted] The poor conductivity and deficient active sites of transition metal oxides lead to low energy density of supercapacitors, which limits their wide application. In this work, double transition metal oxide heterojunctions with oxygen vacancy (V o -ZnO/CoO) nanowires are prepared by effective hydrothermal and thermal treatments. The formation of the heterojunction results in the redistribution of interface charge between ZnO and CoO, generating an internal electric field to accelerate the electron transport. Meanwhile, oxygen vacancies can enhance the redox reaction activity to further improve the electrochemical kinetics of the electrode material. Therefore, the prepared V o -ZnO/CoO can provide a superior specific capacity of 845 C g−1 (1 A g−1). An asymmetric supercapacitor with the V o -ZnO/CoO as positive electrode shows a higher energy density of 51.6 Wh kg−1 when the power density reaches 799.9 W kg−1. This work proposes a synergistic combination of defect and heterojunction engineering to improve the electrochemical properties of materials, providing an important guidance for material design in energy-storage field. [ABSTRACT FROM AUTHOR]